The Environmental Protection Agency (EPA) reckons that 10 million school days are lost because of asthma each year. Many respiratory problems are caused or aggravated by air-borne contaminants, such as those arising from mold and mildew, the EPA says.

To reduce the health risks to students, teachers, and other school personnel, some schools are now using germicidal ultraviolet light to irradiate the cooling coils located within their heating, ventilation, and air conditioning (HVAC) systems.

When heating and cooling systems cycle on and off, condensation occurs in the HVAC units, and they become the perfect breeding grounds for mold and mildew. Portable classrooms are especially susceptible to this health risk.

“Portable classrooms are built a lot tighter than regular school buildings,” said Daniel Jones, business development manager for UltraViolet Devices Inc., a company in Valencia, Calif., that has designed six ultraviolet lights specifically for schools. “There’s no air [flowing] in a natural way, so the building is dependent on the HVAC system for air circulation, and that tends to cause more problems.”

According to the EPA, studies show that one-half of our nation’s schools have problems linked to indoor air quality.

“Moisture damage and humidity can cause mold to grow,” said Christine Miller, spokesperson for the indoor environment division at the Environmental Protection Agency. “When possible, you want to not have mold in your schools.”

Mold and mildew can seriously disrupt learning because they trigger both colds and allergy attacks, she said.

The EPA provides a free online tool kit, called Indoor Air Quality Tools for Schools, that school officials can download and use as a guide to assess and correct their schools’ indoor air quality.

For example, schools should regularly inspect ventilation systems, change filters, and make sure books and boxes are not stacked on HVAC systems. “Make sure what you have is working and then take it to the next step if necessary,” Miller said.

That’s exactly what school officials did at the Ontario-Montclair School District in Ontario, Calif.

The district bought 300 AirSword ultraviolet lights and installed them inside air conditioners in portable classrooms where they had problems with indoor air quality.

“The complaints varied from sneezing to headaches,” said Ralph Arrington, lead HVAC technician at Ontario-Montclair. “Usually the teacher does blame the air conditioning, so we’ve installed these units on the air conditioners.”

Since the lights were installed, the teachers haven’t had any complaints. “I don’t know how much was psychosomatic, but they are happier that we have reacted, and their symptoms disappear,” Arrington said.

The district plans to buy as many as 150 more lights to finish equipping its portable classrooms. “We still get complaints from areas where we haven’t installed the units,” Arrington said.

How it works

The ultraviolet light scrambles the DNA of pathogens, leaving them dead. The AirSword is a permanent fixture hardwired into the heating, cooling, and ventilation systems that is left on all the time so mold, mildew, and different spores never have a chance.

“It irradiates the coils and prevents the pathogens from growing on the coil,” Jones said.

Each bulb offers 8,000 hours or approximately one-year of life.

The bulbs use the same technology as fluorescent lights but the glass is clear instead of opaque. Exposed ultraviolet light can cause burns and blindness so it must be completely concealed within the HVAC system.

“It treats what it sees. If there is mold in the wall it won’t treat that, but it will treat the air being circulated from the heating and cooling system,” Jones said.

There are different ultraviolet lights on the market, but only AirSword lights are designed to fit HVAC systems used in classrooms, Jones said.

“The coil surface in these wall units is 32- to 33-inces long. For UVC to do its job, it has to cover the entire surface,” he said. “It becomes a problem when people install shorter lamps in these units.”

AirSword retails for $500 for one unit and replacement bulbs cost $85. In addition to preventing health problems, Jones said, the AirSword saves schools money because their heating and cooling systems will run more efficiently without any mold or mildew residue.

“There’s a health side of it, and there’s an energy efficiency side of these HVAC units,” Jones said.

Links:

Indoor Air Quality Tools for Schools
http://www.epa.gov/iaq/schools/

Ontario-Montclair School District
http://www.omsd.k12.ca.us/